Does sharp image of distant galaxy shred the fabric of
space and time?
HUNTSVILLE, Ala. -- The sharp image of a galaxy halfway
across the universe might shred modern theories about
the structures of time and space, and change the way
astrophysicists view the "Big Bang," according to two
scientists at The University of Alabama in Huntsville
(UAH).
Their findings might also provide important clues to (and
cause significant upheaval among) researchers trying to
merge two of the most significant scientific theories of
the last century: Einstein's theory of general relativity
and Planck's theory of the quantum.
Using Hubble Space Telescope images of galaxies at least
four billion light years from Earth, UAH's Dr. Richard
Lieu and Dr. Lloyd Hillman tested a popular theory of
modern quantum physics: That time flows in incredibly
small but finite and measurable quantum bits.
Their research findings are scheduled to be published in
the March 10 edition of "Astrophysical Journal Letters,"
and have been released in the journal's website.
Lieu and Hillman used images gathered by the Hubble Space
Telescope to look for patterns that shouldn't be present
if prevailing notions of time quantum were correct.
"I fully anticipated that the pattern wouldn't show," said
Lieu, an associate physics professor at UAH.
Instead, when they looked at Hubble images of galaxies at
least four billion light years from Earth, each image
unexpectedly showed a sharp interferometric pattern -- a
ring around the galaxy.
Using that data, the UAH team was able to determine that
the speed of that light didn't fluctuate by more than a
few parts in 10**-32 as it traveled across the cosmos.
That measurement is significantly more accurate than
should be possible if quantum theories of time and space
are correct.
Their findings will create problems for astrophysicists
and cosmologists who agree with Albert Einstein's theory
that time, gravity and the fabric of space are different
manifestations of the same phenomenon, sort of like
thunder and light are different signatures of lightning.
More recently, when scientists theorized that gravity
is composed of quantum energy "packets" called gravitons,
it made sense that time and space would also be composed
of related quantum bits.
Which brings us to Planck time and Planck length, thought
to be the shortest possible measurements of time and
distance. Both are based on calculations of the most
energetic radiation theoretically possible. There are
twenty million trillion, trillion, trillion Planck time
intervals (5 x 10**-44) in one second. Planck length is
the distance a beam of light would travel in that time --
about 0.000000000000000000000000000000001 (10**-33) cm.
Tying together the theory of gravitons with the shortest
possible measurements of time, quantum theory says time
would move in miniscule, Planck time-sized bits -- like
grains of sand passing chaotically through an hourglass,
or a sequence of jittery freeze frames that on average
last one Planck time rather than a continuous, seamless
flow.
Scientists say time and distances smaller than Planck
scales are "fuzzy," since they can't be measured. If
there is a finite limit to the smallest units of time
and distance, however, that means there are limits on
how accurately scientists can measure things like the
speed of light.
This limitation opens the possibility of Planck-scale
fluctuations in the speed of light, said Lieu. Because
these fluctuations would be extremely small, however,
they would only be evident in light that travels a
great distance. The extended travel gives the slightest
variations in speed an opportunity to spread out and
become noticeable.
(The same principle applies to racing events. A sprinter,
for instance, one percent faster than his opponents might
win a 100-meter race in a photo finish, while a marathon
runner one percent faster than the field would finish a
race hundreds of meters ahead.)
After billions of years, the faster components of a light
wave would be far enough ahead and the slower components
far enough behind that the light's wave front would be
sufficiently distorted (or blurred) to be seen and
measured by a telescope.
It was that distortion that Lieu and Hillman expected to
find in the Hubble images. Not finding that distortion
means time isn't a quantum function, says Lieu, and that
time might flow fluidly and precisely at intervals
infinitely smaller than Planck time.
"If time doesn't become 'fuzzy' beneath a Planck interval,
this discovery will present problems to several
astrophysical and cosmological models, including the Big
Bang model of the universe," said Lieu. "The Big Bang
theory supposes that at the instant of creation, the
quantum singularity that became the universe would need
to have infinite density and temperature. To avoid that
sticky problem, theorists invoked the Planck time. They
said if the instant of creation was also a quantum event,
when space and time were both blurry, then you don't need
infinite density and temperature at the start of the Big
Bang.
"If time moves along like business as usual even at
Planck scales, however, you have to reconcile the Big
Bang model with an event that isn't just off the scale,
it's infinite!"
[NOTE: An image support this release is available at
http://www.uah.edu/News/2003news/ring_image.jpg (14KB)]
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